Substitution of sugarbeet pulp for alfalfa hay in diets for growing rabbits

Four rabbit diets were formulated to study the effect of a progressive inclusion (0, 100, 200, and 300 g kg − 1) of sugarbeet pulp (SBP) substitute for alfalfa hay (AH). The control diet contained 500g kg−1 of AH and 190 g kg−1 acid detergent fibre (ADF) on a DM basis. In Experiment 1, 32 Californian x New Zealand White rabbits were used to determine dietary nutrient digestibility. The inclusion of SBP quadratically increased (P < 0.01) digestibility coefficients of NDF, ADF and gross energy, showing a maximum for the diet containing 200g kg−1 of SBP. Crude protein digestibility linearly increased with SBP inclusion (P < 0.05). In Experiment 2, 36 rabbits fed the same diets as in Experiment 1 were used to determine several digestive traits and the efficiency of utilization of dietary energy for growth. Dietary inclusion of SBP did not affect either the concentrations of ammonia (66 mg of N-NH3 per litre) and total VFA (50.3 mmol l−1) or the molar proportion of VFA (767, 62 and 171 mmol mol−1 VFA of acetate, propionate and butyrate, respectively) in the cecal digesta. The concentration of starch in the ileal digesta was also unaffected by diet (7.7 g kg−1 of DM, as average). The weight of cecal contents increased (P < 0.05) and the pH of cecal contents decreased (P < 0.05) when SBP proportion in the diet increased. The efficiency of utilization of dietary digestible energy for growth was not influenced by dietary SBP inclusion (0.224, as average).